Question 1

Which of the following best describes the primary function of mucin as a surface barrier in the innate immune system?

Accepted Answer

Mucin forms a sticky physical barrier that traps microorganisms, preventing their entry into deeper tissues.

Question 2

A patient with a genetic deficiency in defensins is likely to experience which of the following consequences?

Accepted Answer

Increased susceptibility to bacterial infections because of decreased antimicrobial peptide activity.

Question 3

Which of the following is a key difference between innate and adaptive immune systems?

Accepted Answer

Adaptive immunity involves memory cells that provide long-lasting protection, while innate immunity does not.

Question 4

Which of the following best describes the role of natural killer (NK) cells in the innate immune system?

Accepted Answer

NK cells directly attack and induce apoptosis in virus-infected and cancerous cells.

Question 5

During inflammation, which sequence of events occurs first?

Accepted Answer

Release of inflammatory chemicals such as histamine.

Question 6

A patient develops a fever in response to a bacterial infection. Which of the following is a beneficial effect of fever?

Accepted Answer

Fever enhances the activity of phagocytes and inhibits bacterial growth by raising body temperature.

Question 7

Which of the following statements about interferons (IFNs) is correct?

Accepted Answer

Interferons are proteins released by virus-infected cells that help protect neighboring cells from viral infection.

Question 8

Which of the following best defines a 'complete antigen'?

Accepted Answer

A molecule that possesses both immunogenicity and reactivity, capable of stimulating and reacting with immune cells.

Question 9

Which of the following is true regarding haptens?

Accepted Answer

Haptens are small molecules that become immunogenic only when attached to larger carrier proteins.

Question 10

Which cell type is primarily responsible for humoral immunity?

Accepted Answer

B lymphocytes

Question 11

Antigen-presenting cells (APCs) play a crucial role in adaptive immunity by:

Accepted Answer

Presenting processed antigens to T lymphocytes to initiate their activation.

Question 12

Which of the following steps occurs first in the development of B and T lymphocytes?

Accepted Answer

Origin in primary lymphoid organs (bone marrow for B cells, thymus for T cells)

Question 13

A patient is exposed to a new pathogen. Which sequence best describes the steps in adaptive immune cell development?

Accepted Answer

Origin → Maturation → Seeding → Antigen encounter and activation → Proliferation and differentiation

Question 14

Which of the following best describes the function of antibodies?

Accepted Answer

Antibodies bind to antigens, neutralizing them and marking them for destruction by other immune cells.

Question 15

A patient with a deficiency in complement proteins would most likely experience:

Accepted Answer

Impaired ability to lyse pathogens and enhance phagocytosis.

Question 16

Which of the following equations best represents the relationship between antigen concentration ($$[Ag]$$), antibody concentration ($$[Ab]$$), and immune complex formation ($$[IC]$$)?

Accepted Answer

$$[IC] = k 	imes [Ag] 	imes [Ab]$$

Question 17

A patient with an autoimmune disorder is producing antibodies against self-antigens. Which of the following best explains this phenomenon?

Accepted Answer

Failure of self-tolerance during lymphocyte maturation.

Question 18

Which of the following scenarios best illustrates the concept of immunogenicity?

Accepted Answer

A molecule stimulates the proliferation of lymphocytes and the production of antibodies.

Question 19

Which of the following is a real-life example of the adaptive immune system in action?

Accepted Answer

A person receiving a vaccine and developing memory cells that protect against future infection.

Question 20

A patient is exposed to a virus for the first time. Which of the following best describes the sequence of immune responses?

Accepted Answer

Innate defenses (surface barriers and internal defenses) respond first, followed by adaptive defenses (humoral and cellular immunity).

Study Guide: The Immune System (Innate & Adaptive Defenses)

Study Guide - Practice Questions

Study Guide - Flashcards